In general, a numerical controlled machine tool accommodates a number of tools, performs a cutting processing by calling a particular tool, and accommodates again the tool after completing using the tool. Here, the tool is accommodated in a tool magazine, and the tool is carried between the tool magazine and a spindle by an automatic tool changer (ATC).
Meanwhile, key blocks are disposed at the tool pocket of the tool magazine and the spindle, and key grooves, which accommodate the aforementioned key blocks, are formed at all tools, and therefore when the tool is mounted at the tool pocket or the spindle, the tool is aligned in a particular direction in which the key block and the key groove are fitted with each other.
In addition, in a case in which a shape of the tool is asymmetric based on an axis line or the tool has a large diameter, of which a radius of rotation is large, the tool may not be smoothly accommodated in the tool magazine, and may interfere with the other mechanical structures, and therefore the tool is accommodated in a state in which a phase of the tool is perpendicularly rotated.
On the other hand, a phase of the key block of the tool pocket and a phase of the key block of the spindle may form a right angle, and in this case, because the tool may not be exchanged by a general automatic tool changer, a tool carrier is used to rotate a phase of the tool.
The tool carrier of the related art will be described with reference to FIGS. 1 and 2.
A center shaft 12 is disposed at one side of a base plate 10, a swing unit 20 is rotatably installed at the center shaft 12, an actuator 30 is connected to one side of the swing unit 20 by the media of a link 32, and a carrier unit 40 is installed at the other side of the swing unit 20.
The aforementioned actuator 30 is driven by hydraulic pressure or pneumatic pressure so that a rod 31 extends/contracts, the aforementioned link 32 is connected to an end of the rod 31, and the actuator 30 is configured to be installed at one side of a machine tools frame 36 by a shaft pin 34 so that a posture of the actuator 30 may be rotated about the shaft pin 34.
Meanwhile, the aforementioned swing unit 20 turns by a drive of the aforementioned actuator 30, a section in which the swing unit 20 turns is from an original position A of the carrier unit 40 to a target position B of the carrier unit 40.
The aforementioned carrier unit 40 has a tool pocket unit 50 which is rotatably provided in a carrier body 44, and a rotating axis of the aforementioned tool pocket unit 50 is perpendicular to a rotating axis of the aforementioned swing unit 20.
Meanwhile, the aforementioned tool pocket unit 50 has a pin shaft 52 which is rotatably disposed in the aforementioned carrier body 44, and a pin 54 is installed to protrude at one side of the pin shaft 52.
In addition, first and second alignment grooves 52a and 52b are formed at the aforementioned pin shaft 52, the first and second alignment grooves 52a and 52b form 90° based on a center of the pin shaft 52, a ball stopper 58 is provided at one side of the carrier body 44, and the ball stopper 58 is inserted the first alignment groove 52a or the second alignment groove 52b to prevent the tool pocket unit 50 from being randomly moved after the rotation of the tool pocket unit 50 is completed.
In addition, a tool pocket 55 is formed at a front side of the tool pocket unit 50 to accommodate a tool T, and a key block 56 is disposed at one side of the tool pocket 55.
That is, as a key groove formed at the tool T and the aforementioned key block 56 are fitted with each other when the tool T is accommodated in the aforementioned tool pocket 55, the tool T is always aligned as a particular phase.
Meanwhile, a first pin guide unit 60a and a second pin guide unit 60b are installed at an upper side of the aforementioned base plate 10, the first pin guide unit 60a is installed at a position when the movement of the carrier unit 40 toward the tool magazine is completed, and the second pin guide unit 60b is installed at a position when the movement of the carrier unit 40 toward the spindle is completed.
In addition, the aforementioned first and second pin guide units 60a and 60b come into contact with the pin 54, as illustrated in FIG. 2.
Therefore, when the tool carrier 40 turns to return to the original position A, the pin 54 comes into contact with the first pin guide unit 60a at any moment, and when the tool carrier 40 further rotates, the pin 54 rotates the pin shaft 52 to turn a direction of the tool pocket unit 50.
In contrast, when the tool carrier 40 turns to the target position B, the pin 54 comes into contact with the second pin guide unit 60b at any moment, and when the tool carrier 40 further rotates, the pin 54 rotates the pin shaft 52 to turn a direction of the tool pocket unit 50.
That is, in the aforementioned tool pocket unit 50, phases of the pocket unit 50 and the tool T are changed according to whether the tool carrier 40 is positioned at the original position A or the target position B.
However, the aforementioned tool carrier of the related art has the following problems.
The tool T reciprocates to the original position A or the target position B in a state of being accommodated in the tool pocket unit 50, and as the tool T rotates from the moment when the pin 54 and the first and second pin guide units 60a and 60b come into contact with each other immediately before the tool T arrives at the target position, the phase of the tool T is changed.
However, there is a problem in that impact is generated at the moment when the pin 54 and the first and second pin guide units 60a and 60b come into contact with each other, as described above, and the tool T is moved away from the tool pocket unit 50 due to the impact.
Particularly, because a tool T provided for a special purpose is formed to be asymmetric with respect to a rotating axis, a center of gravity of the tool T is concentrated toward any one side, and the tool T may be in an unstable state when the tool T is accommodated in the tool pocket unit 50.
In addition, because a center of gravity of the tool having a large diameter, of which a diameter is large is also concentrated outward, the tool T may be in an unstable state when the tool T is accommodated in the tool pocket unit 50.
In a case of the special tool T of which a center of gravity is concentrated in one side, as describe above, there is a problem in that impact occurs when the pin 54 and first and second pin guide units 60a and 60b collide with each other at the time when the arrival at the original position A or the target position B is completed, and the tool T is moved away from the tool pocket 55 immediately after the impact.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.